1. Field of the Invention
One embodiment of the present invention relates to a semiconductor device. One embodiment of the present invention also relates to a method for manufacturing the semiconductor device.
Note that one embodiment of the present invention is not limited to the above technical field. For example, one embodiment of the present invention relates to an object, a method, or a manufacturing method. One embodiment of the present invention relates to a process, a machine, manufacture, or a composition of matter. One embodiment of the present invention relates to a micromachine, a display element, a display device, or an electronic device.
Note that in this specification and the like, a semiconductor device typically means a device that can function by utilizing semiconductor characteristics. Thus, a semiconductor element such as a transistor or a diode and a semiconductor circuit are semiconductor devices. A display device, a light-emitting device, a lighting device, an electro-optical device, a memory device, an electronic device, and the like may include a semiconductor element or a semiconductor circuit. Thus, a display device, a light-emitting device, a lighting device, an electro-optical device, an imaging device, a memory device, an electronic device, and the like include a semiconductor device in some cases.
2. Description of the Related Art
A shift register which includes a plurality of register circuits and in which data stored in the register circuits is sequentially transferred in synchronization with a clock signal is used for various devices. For example, a shift register is used for a display device including a plurality of pixels provided in a matrix, an imaging device including a plurality of imaging elements, or a memory device including a plurality of memory elements.
In recent years, display devices and imaging devices have been required to increase their resolution, and memory devices have been required to increase their capacity. Accordingly, the number of register circuits is increased in a shift register, and the frequency of a clock signal is increased. Thus, the power consumption of the shift register is increased; as a result, the power consumption of a semiconductor device is increased.
Patent Document 1 describes a technical idea that the power consumption of a semiconductor device is reduced by stop of supply of a clock signal to a register circuit that does not need to be operated.